Process and apparatus for conversion of hydrocarbon oils



RL CROSS Dec. 27, 1932.

PROCESS AND APPARATUS FOR CONVERSION OF HYDROCARBON OILS Filed Sept. 30, 1926 .buv

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Mille-$5 Patented Dec. 27, '1932 UNITED STATES PATENT OFFICE ROY CROSS, OF KANSAS CITY, MISSOURI,

ASSIGNOR, BY MESNE ASSIGNMENTS, TO

GASOLINE PRODUCTS COMPANY, INC., OF WILMINGTON, DELAWARE, A CORPORA- TION OF DELAWARE Application led September 30, 1926. Serial No. 138,806.

This invention relates to improvements in a process and apparatus for the conversion of hydrocarbon oils, and refers more particular, ly to a process for the cracking of relatlvely heavy oils into lighter oils having the characteristics of gasoline or the like.

Among the objects of the inventlon are to provide a process in which a cracking stock 1s heated to a conversion temperature 1n the heating zone and is thence passed to a reaction chamber of an enlarged cross sectional diameter relative the .heating Zone, wherein the temperature is maintained substantially the same as that arrived at in the heating zone, 1n order to continue the cracking instituted in the furnace or heating coil; to provide a proc- `ess in which the oil, after passing through the reaction zone, is cooled and an oxidizing gas introduced thereto to increase the formation of certain desirable hydrocarbon derivatives having characteristics which improve the anti-detonating qualities of the finished motor fuel; to provide a process in which subsequent to the introduction of an oxidizing gas the oil products are passed to a zone of reduced pressure and there vapor-ized, the vapors being subjected to a refluxing action and final condensation while certain of the heavier products are returned for retreatment in the system, and in general to provide a process hereinafter described.

The single figure is a side elevational View with parts in section and 'parts broken away.

At 1 in the drawing is shown a furnace,

consisting of a combustion chamber`2 and a' tube compartment 3. The furnace is preferably heated by means of gas burners, not shown, positioned adjacent to, or in the combustion compartment, the combustion gases passing fromthe combustion compartment into the tube chamber containing a continueus coil 4. and discharged from the bottom of the tube chamber through a Hue 5. The discharged end of the tubes 4 is connected by a line 6 to the reaction chamber 7, which is preferably formed from a single ingot of forged steel and heavily insulated to prevent loss of heat by radiation. VEnd openings, affixed to the reaction chamber, are removable to facilitate the cleaning of the chamber.

The heating coil 4, fittings and connections, together wlth the reaction chamber are of materials adapted to withstand high pressures and high temperatures. The opposite end of the reaction chamber has communication through a pipe 8 to a cooling or oxidizing zone 9, which is also constructed of heavy material to withstand pressures similar to those maintained in the heat and reaction chamber. This retort 9 has removable end plates to assist in the cleaning thereof, and also in making replacement or repairs of apparatus contained in the retort.

Within both the reaction chamber and the retort 9 are perforated pipes l0 and 11 respectively. Two compressors 12 and 13 have connections with the perforated pipes by means of the lines 14, 15 and 16. A line 17 connects the pipe 16 with the line 14, so that introduction of materials may be made from either compressor to either of the perforated pipes 10 or 11. The retort 9 has connection with an evaporator 18 through a transfer line 19, controlled by a reduction valve 20. The top of the evaporator has a vapor line connection 21 with the dephlegmatng tower 22, which in turn has a vapor line connection 23 with the condenser coil 24 positioned in the condenser box 25. The discharge end of the condenser coil terminates in a line 26 which leads to the gas separator 27. This gas separator has an upper gas relief line 28 controlled by a valve 29, and a liquid level drawoii' line 30, regulated by a valve 31.

A draw-off line 32 connected into the bottom of the evaporator is controlled by a valve 33 manipulated by an automatic liquidlevel regulating mechanism dia-grammatically shown at 34. The draw-off line 32 leads to a cooler 35 where the bottoms withdrawn from the evaporator are cooled before being directed to storage to the line 36. A similar draw-off line 37, connected into the bottom of the dephlegmator 22, is controlled by a valve 38, the latter being manipulated by 'an automatic liquid level regulating dexvice 39, similar to that shown at 34. The line 37 directs the recycled stock or reluxed condensate to a tank 40, from which it may be diverted from the system through a line 41, controlled by a valve 42, or returned and recycled through the system by means of a pipe 43, communicating With the suction side of the pump 44, Which discharges through the line 45 to the heating coil.

Fresh charging stock is supplied to the system through the line 46 and pump 47, being either directed through the heat eX- changing coil 48, positioned within the retort 9, through Which the hot oil is being circulated, or through the by-pass line 49, or regulated quantities through both the pipes 48 and 49 to secure the desired degree of cooling of the oil passing through the retort 9. This control of the quantity of the stock passing through the retort as a cooling medium is re ulated by valves 50 and 51.

n operation charging stock is supplied, as suggested, from any convenient source through the pipe 46, and is charged by means of the pump 47, through the line 52 and thence either through the coil 48, positioned in the retort 9, or a portion through thecoil and a portion through the by-pass line 49. These lines unite to form the pipe 53, which directs the oil to the heating coil 4. In the heating zone the oil is brought toa conversion or cracking temperature, the velocity of circulation being so regulated asto prevent accumulation of carbon in the tubes. The heating is also regulated to the extent that suiicient heat will be added to the oil to continue the cracking, or conversion when the oil is passed on to the reaction chamber.

In the reaction chamber the oil is collected in a considerable body and due to the high temperature conversion is continued. In order to `maintain the desired cracking temperature thereanay be added in this stage a gaseous material, which combines with the hydrocarbon by exothermic combination. Such gases as oxygen or air, added to the reaction stage by means of a compressor 12, through the line 14, and perforated pipe 10 would produce this result. Operating conditions must be regulated, however, so that the introduction of gaseous material at this high temperature and pressure does not produce the combination of objectionable materials, such as Water vapor. Applicant has found that in this process the production of moisture at these high temperatures and pressures is objectionable on account of the iiuctuation of operating conditions produced by the eX- istence of the Water vapor in the system Furthermore it has been found from actual operation that due to the reactivity of the oil at thetemperature and pressures of the reaction stage it is better to reduce somewhat thel temperature of the oil before the injection of gaseous materials which produce in the oil body anti-knock or anti-detonating properties of the ultimate distillate. Such material, as the alcohols, ketones and other products resulting from the introduction of Oxdizing vapors, can be better formed at the temperatures to Which the oil is brought in the retort 9 by cooling with the circulation of the charging stock through this stage to reduce the temperature of the oil to the extent that the combination of the gaseous material with the oil is more satisfactorily effected. For this reason connections are made with the compressor 13 and With the perforated pipe 11 so that the gaseous material may be injected into the retort 9, through which oil is passed at a temperature somewhat lower than the temperature maintained in the reaction chamber. At the point of discharge from the oxidizing zone 9 the pressure is released and' the oil introduced into the evaporating stage Where immediately a separation into vapor and liquid takes place. dueto the reduction of pressure and the contained heat in the oil.

The vapors passing overhead from the evaporator are subjected to a dephlegmating or refluxing action in the tower 22, which is preferably of the bubble type construction, the reiluXed vapors passing otf from the'top of the dephlegmator through the line 23 to the condenser 25. thence to the gas separator 27. The gas removed through the line 28 may be further stripped or used direct in the burners of the furnace for fuel purposes. The liquid distillate is drawn oft' from the bottom ofthe gas separator.

If it is necessary to reduce the temperature of the oil in the retort 9 to the extent that satisfactory evaporation is not effected bv the reduction of pressure on its introduction into the evaporating stage, this stage may be heated by the injection of steam, either super-heated or otherwise through the pipe 54. The bottoms from the evaporator' as explained are cooled and directed to storage While the refluxed condensate drawn ofi from thedephlegmating tower is diverted from the system, lor recycled.

As typical of the operating conditions, oil charged to the furnace is heated to temperatures ranging from 800 to 1050 F., While pressures of from 50() to 2000 pounds per square inch are maintained upon the oil undergoing treatment. Any temperature drop in the reaction chamber will be produced wholly by the endothermic action of cracking or by loss of heat through radiation. As suggested. this temperature may be maintained by the introduction of'oxidizing gases. The oil is cooled in the retort 9 to temperatures ranging from 350 to 600 F. depending upon the oil undergoing treatment and the gas introduced in this zone.

The pressure on the oxidizing zone or the retort 9 may be substantially that of the heatin;r coil. and reaction chamber. or it may be reduced somewhat by manipulation of the valve 55 in the line 8. The temperature in the evaporating stage will vary according to the temperatures in the preceding stages, but will in all events be` considerably less, due to the loss ofheat by vaporization. The purpose of the cooling, or oxidizing zone is to drop the temperature to that point where excessive reaction will not occur, or the reaction will be limit-ed to the extent that the desired products will be produced rather than objectionable water and precipitated carbon. It has been found from actual experimentation that oxygen when introduced into the hydrocarbon molecule combines more readily to produce desirable properties in the gasoline at lower temperatures, such as temperatures ranging from 350 to 7000 F. The oil in the oxidizing zone is cooled preferably by heat exchange with the charging stock, and in place of a single zone, as shown, the heat exchange may be made in a double pipe arrangement with the injection of the gaseous materials effected in a separate retort or chamber. The desirable products produced in the ultimate distillate by the introduction of air or other oxygen bearing gas are certain hydrocarbon derivatives of the nature of acetone, aldehydes, organic esters, organic acids and the like.

I claim as my invention:

l. In an apparatus for converting hydrocarbon oils, a combination with means for heating the oil in a restricted stream in a furnace, a reaction chamber connected thereto, means for reducing the temperature of the oil discharged from the reaction chamber, and means vfor maintaining pressures in excess of 500 pounds per square inch on the heating means, the reaction chamber and the cooling means, separate means for injecting gaseous material into the reaction chamber and into the cooling means, evaporating, dephlegmating and condensing means serially connected to the cooling means and means for reducing the pressure upon the oil undergoing treatment between the cooling and evaporating means.

2. A process for the conversion of hydrocarbon oils comprising the steps of raising the oil to a cracking temperature in a heating zone, passing the heated oil to an enlarged reaction zone, directing the oil thence to a zone of reduced temperature, introducing to the oil in the reduced temperature zone, an oxygen bearing gas adapted to react with the oil while maintaining the pressure in excess of five hundred pounds per square inch upon the oil undergoing treatment. and cooling the charging oil in said reduced temperature zone by circulating oil to be treated in indirect heat exchange relation therewith.

3. A process for the conversion of hydrocarbon oils comprising raising the oil to a cracking temperature in a heating zone, passing the heated oil to an enlarged reaction zone, passing the oil from said reaction zone to a zone of reduced temperature in which the oil is vmaintained at a temperature materially below 700F. and substantially in the liquid phase, introducing an oxygen containing gasinto said reaction zone to effect heating of the loil in said reaction zone, introducing an oxygen containing gas into the zone of reduced temperature to produce antiknock hydrocarbon derivatives of oil, and cooling the oil' in said reduced temperature zone to prevent the formation of undesirable reaction products.

4. A process for the conversion of hydrocarbon oils comprising raising the oil to a cracking temperature in a heating zone, passing'the heated'oil to an enlarged reaction zone, introducing an oxygen containing gas into said enlarged reaction zone to maintain a high temperature therein, directing th oil from the reaction zone to a zone of reduced temperature in which the oil is Amaintained at a temperature materially1 below 700 F. and substantially in the liquid phase, introducing an oxygen containing gas into the oil in the zone of reduced temperature to produce antiknock hydrocarbon derivatives of oil while maintaining the pressure in excess of five hundred pounds per square inch and cooling the zone Vof reduced temperaturel to prevent the formation of undesirable products.

A process for the conversion of hydrocarbon cils, comprising the steps of raising the oil to a cracking temperature in a heating zone, passing the heated oil to an enlarged reaction zone, directing the oil thence to a zone of reduced temperature in which the oil is maintained at a temperature materially lbelow 700 F. by an indirect heat exchange with the oil to be heated and substantially in the liquid phase and introducing into the oil in the reduced temperature zone an oxygen bearing gas adapted to react with the oil while maintaining the pressure in excess of 500 pounds per square inch upon the oil undergoing treatment to produce anti-knock hydrocarbon derivatives in the oil.

6. A process for the'conversion of hydrocarbon oils, comprising the steps of raising the oil to a cracking temperature in a heating zone, passing the oil to an enlarged reaction zone without cooling, reducing the temperature of the oil by passing it through a zone in an indirect heat exchange with the oil to be heated, supplying an oxygen bearing gas to the oil to produce anti-knock derivatives therein and maintaining upon the zones pressures in excessl of 500 pounds per square inch, discharging the oil from the oxidizing stage into a zone of reduced pressure and distilling oit the lighter fractions, refluxing the 'apors evolved by such distillation and subjet-ting them to a' final' 'condensing action.

v 7.l A processfor the conversion of hydrocarbon oils, comprising the steps of raising the oil to a cracking temperature in a heating zone, passing the oil to an enlarged reaction zone without cooling, reducing the temperature of the oil by passing it through a zone in an indirect heat exchange with the oil to be heated, supplying an oxygen bearing gas to the oil to produce anti-knock hydrocarbon derivatives therein and maintaining upon the zones pressures in excess of 500 pounds per square inch, discharging the oil from the oxidizing stage into a zone=of reduced pressure, and distilling oii1 the lighter fractions, refluxing the vapors evolved by such distillation and recycling the reiiuxed condensate through the system for retreatment, and subjecting the uncondensed vapors to a final condensing action.

8. A process for the conversion of hydrocarbon oils, comprising the steps of raising the oil to a cracking temperature in a heating zone, passing `the oil to an enlarged reaction zone Without cooling, discharging the oil from the reaction zone into a zone of reduced temperature in which the oil is maintained at a temperature materially below 700 F. and substantially in liquid phase by an indirect heat exchange with the oil being supplied to the system, supplying an oxygen bearing gas to the oil in the reduced temperature zone to produce anti-knock hydrocarbon derivatives therein and maintaining upon the zones pressures in excess of 500 pounds per square inch, discharging the oil fromthe reduced temperature zone into a zone of reduced pressure and distilling off the lighter fractions, reiiuxing the vapors evolved by such distillation and subjecting them to a fina-l condensing action.

9. A process for the conversion of hydrocarbon oils, comprising the steps of raising the oil to a cracking temperature in a heatling zone, passing the'oil to an enlarged reaction zone Without cooling, reducing the temperature of the oil by passing it through a zone in an indirect heat exchange with the oil to be heated, supplying an oxygen bearing gas to the oil in the reduced temperature zone to produce anti-knock derivatives therein and maintaining upon the zones pressures in excess of 500 pounds per square inch, discharging the oil from the reduced temperature zone into a zone of reduced pressure, adding heat to the zone of reduced pressure to assist in the distillation of the volatile fractions from the liquid hydrocarbons, distilling ofi' the lighter fractions, reiiuxing the vapors evolved by such distillation and subjecting them to a linal condensing action.

10. A process for the conversion of hydrocarbon oils comprising heating the oil to a conversion temperature, maintaining the oil at conversion temperature by introducing an oxidizing gas thereinto, passing the oil into a cooling and oxidizing zone, passing an oxidizing gas into contact with the oil continuously as it passes through said cooling and oxidizing zone and simultaneously reducing the temperature of the oil moving through said cooling and oxidizing zone, to that temperature at which oxidized hydrocarbons raving anti-knock properties are formed, by passing feed oil in extended indirect heat Aexchange relation with the oil in said zone thereby maintaining the temperature sufficiently low to form thedesired oxidized liydrocarbon derivatives.

1l. A process for the conversion of hyd-rocarbon oils comprising heating the oil to a conversion temperature, maintaining the oil at conversion temperature by introducing an oxidizing gas thereinto, passing the oil into a cooling and oxidizing zone, passing an oxidizing gas into cont-act with the oil continuously as it passes through said cooling and oxidizing zone and simultaneously reducing the temperature of the. oil moving through said cooling and oxidizing zone, to that tem erature at which oxidized hydrocarbons Ihaving anti-knock properties are formed, by passing feed oil in counter-current indirect heat exchange relation with the oil in said zone thereby maintaining the tem perature suiiiciently low to form the desired oxidized hydrocarbon derivatives.

ROY. CROSS. 

